Why does a designed email look different in my inbox?

The canvas you edit on is an approximation, and it is drawn at whatever width your browser gives the middle pane, which is usually narrower than the 600 pixels the real email uses. Anything that depends on width, especially alignment and where a line of text wraps, reads a little differently there. The Desktop and Mobile views in the top bar render the real email, and a Send test to your own inbox is the final word.

Three differences are worth knowing before you build a template around them.

Columns do not stack on a phone. A two or three column row stays side by side on a narrow screen and shrinks to fit rather than rearranging into one column. Use columns for things that survive being narrow, like a logo beside a heading or a row of links, and put anything with real paragraphs in a full width Section.

Images are blocked until you are trusted. Most email programs will not load pictures from a sender the reader has not written to or saved as a contact. What many recipients see first is your alt text where the picture should be. Adding images to an email template covers how to write it.

Outlook on Windows draws email with a different engine. It is stricter than a browser about spacing and about image formats, which is part of why the designer converts what you upload. If something looks right everywhere except Outlook, that is usually the reason.

One thing is different on purpose: links on the canvas do not open when you click them, so that clicking selects the block for editing instead. They work normally in the preview and in the sent email.

For the rest of the editor, see designing an email template with blocks.